spotlight The Slender-billed

(possibly extinct) by BirdLife – with no quest verified sightings since the early 1980s. We hope it can be proven that Slender- billed Curlew still exists.The most urgent On the very brink of , the once numerous priority is to thoroughly search sites Slender-billed Curlew is a true enigma. Tim Cleeves, where the species is known to have wintered previously, as well as potential Nicola Crockford and Peter Köhler report on a last- moulting sites, although no moult site has ditch attempt to find the – and how you can help. yet been identified. It is likely to be easier to search the lender-billed Curlew is the Gretton et al 2002).The last flocks of more relatively few discrete, identifiable rarest bird in the Western than 100 were seen in Morocco at Lagune candidate sites in the putative wintering Palearctic. It is one of the five de Puerto Cansado, Khnifiss, in January and moulting range than the vast Sbird species in – and 1964 (500-800 ) and at Oued continuous area of potential breeding 190 in the world – most threatened with Chebeika in December 1974 (123 birds). habitat.Thus, unless stable isotope research global extinction, and classified as However, Slender-billed Curlew is narrows the search to within a radius of Critically Endangered by BirdLife easily overlooked and challenging to about 100-200 km, it is less of a priority International and the IUCN. identify, and could be present in countries to continue the ‘needle in the haystack’ There have been no verified records such as Iraq and Iran, which have been search for Slender-billed Curlew in its anywhere since 1999, when birds were relatively inaccessible to skilled birders in probable breeding range in Russia and seen in Greece in April and Oman in recent years. Kazakhstan. February and August.This last sighting There is a higher chance of catching involved three juveniles, indicating that Last chance birds at wintering sites, where they stay breeding must have occurred that year.At This article is intended to help launch a for prolonged periods, rather than passage the last-known regular wintering site, ‘final push’ to find this enigmatic species sites that they may go through quickly. Merja Zerga in Morocco, there have been before it is too late. If we lose Slender- This makes satellite tagging easier, which no verified records since 1995. billed Curlew, it will be the first is vital to find the breeding, passage, The only verified records of nesting extinction of a European bird since Great moult and wintering sites in order to take Slender-billed all date from the Auk in June 1844 and Canary Islands conservation action for the species. first quarter of the 20th century and Oystercatcher in 1981 (BirdLife We hope this article will inspire readers occurred near Tara, east of the Urals in the International 2008a). Eskimo Curlew, the to plan their birding holidays and organise Omsk region of south-west birds’ close relative in the Nearctic, is expeditions to the most likely Slender- ៑ CHRIS GOMERSALL (WWW.RSPB-IMAGES.COM) (Ushakov 1909, 1912, 1916 and 1925; already classified as Critically Endangered billed Curlew sites. In addition, the special

This adult Slender-billed Curlew, one of several that used to winter at Merja Zerga, Morocco, in the early 1990s, was last seen in February 1995. There have since been no verified records at the site.

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WWW.BIRDWATCH.CO.UK JANUARY 2009 • BIRDWATCH 43 Species spotlight

laminated ‘toolkit’ enclosed exclusively Past records autumn. Almost a third are from another with this month’s Birdwatch has been eight countries: Ukraine – 33 in all seasons, designed to be taken into the field, and The Slender-billed Curlew Working Group but more in autumn; Serbia – 30 in autumn (SBCWG) collects and documents all and spring, but also in summer; Tunisia – includes an identification guide and advice records of the species on a database; visit 29 mainly winter; Turkey – 24, in all on steps to take if you are lucky enough to www.slenderbilledcurlew.net. It separates seasons but more in summer; Bulgaria – find a potential Slender-billed Curlew. those listed before and after 1990. It also 23 in spring, autumn and winter; Iran – 19, distinguishes three categories of records: mainly in winter; Romania – 18 in all Breeding ecology ● Verified records: these are authenticated seasons, but mainly autumn; and Russia – Like Eskimo Curlew in , in by national organisations – rarities 17, mainly in spring but some also in committees, BirdLife partners and so on – summer and autumn. the 19th century Slender-billed Curlew or, in the absence of such bodies, by other About 85 per cent of the verified records was regarded as common in Europe in experts. They include records regarded as since 1900 are from these 12 main range countries such as Romania, Hungary, Italy ‘confirmed’ by Gretton (1991 and 1994) states, all of which have had at least 10 and Greece. It outnumbered the two other unless proved otherwise by the relevant verified records during that period. There European curlew species – Eurasian Curlew national organisations or by the original are another 12 range states with between and Whimbrel – in several areas, including observer. three and nine verified records since 1990: ● Unverified records: these are mainly summer – Kazakhstan; mainly Sicily, Malta,Tunisia, Morocco and Algeria, unsubstantiated by any details such as a autumn – Poland, Austria, Malta, Iraq and and sometimes occurred in spectacular, description or photograph, or are those on Yemen; mainly winter – Algeria, Egypt, Iraq, thousands-strong flocks. Even then, before which a national organisation has not yet Oman, France and The Netherlands; mainly its dramatic decline, which was probably reached a decision or suggests that there spring – Bosnia-Herzegovina and Cyprus. due to overhunting and exacerbated by is doubt, but are not yet rejected. This Only about 20 per cent (128) of the habitat loss, very little was known about includes those treated by Gretton (1991 verified records since 1900 have been of and 1994) as unconfirmed, unless proven more than three birds, with just over half the bird’s ecology. otherwise. referring to single birds. According to Ushakov’s 1925 paper, ● Rejected records: these have been Slender-billed Curlews have often been confirmed nest sites near Tara, including a rejected by a national organisation or other seen in close association with Eurasian colony of 14 nests, were in an extensive relevant experts. Curlews. Associations with other quaking peat bog with dense cover of More than half of the 617 verified such as Whimbrel, Black-tailed , sedge mixed with Mares’Tail Equisetum, records for 1900 to 1999 come from four Grey Plover, Northern Lapwing and countries: Italy – 99 verified records, mostly species are not usually close (Gretton 1991). with willow, birch and pine present.The spring but some also in autumn and winter; It should be borne in mind that the birds arrived in the area from 10 May. Greece – 85, all seasons but mainly in number and distribution of records are With such a small sample and an spring; Morocco – 76, mainly in winter; and heavily influenced by the number and account dating back more than 80 years, Hungary – 66, all seasons but mainly in distribution of skilled birdwatchers. when the species was already in decline, it would be wrong to conclude that all Slender-billed Curlews bred or breed in marsh, or that the breeding dates remain the same now as they did in Ushakov’s day.The bog-forest transitional habitat he described during the early 20th century appeared similar in 1990 but by 1997 was already destroyed, having become afforested, and with adjacent areas cultivated (Gretton et al 2002). ADAM GRETTONADAM

All verified records of Slender-billed Curlew since 1900. Summer: June-July (45 records); autumn: August-November (196); winter: December-February (167); Autumn Summer spring: March-May (185). Spring Winter COURTESY OF RSPB

The only known breeding site for Slender-billed Curlew was in the forest- steppe zone in the vicinity of Omsk and Novosibirisk.

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Danilenko et al (1996) analysed Britain’s sole record vegetation maps in these areas and in of Slender-billed other locations where birds had been Curlew (left, with recorded during summer in the 1800s. Eurasian Curlew), They summarised the breeding habitat at Druridge Bay, requirements as forest-steppe: “Open, Northumberland, locally wet areas with dense sedge or dates back to early May 1998. grass vegetation, with patches of bare JIM PATTINSON ground, relief which is not flat (moderate elevations and depressions), and with complete by October-December, which 1997), Kazakhstan (July-September adjacent shrubs or woodland patches excludes flight feathers, upperwing 1998), Russia (Tumen plains and Omsk formed by deciduous trees and/or pines.” coverts, tail, some scapulars and most region, 1999), Iran (January-February Such habitat within western Siberia tertials. In spring, most feather tracts are 2000), Morocco (Lagune de Khnifiss, extends in area to between 200,000 and renewed again, but flight feathers remain December 2001),Yemen (November 400,000 sq km. unmoulted. 2001-January 2002), Iran (January Indeed, Ushakov’s observations were 2002),Tunisia (January 2003), Libya made towards the northern edge of the Habitat preferences (January 2005), Ukraine (July-August forest-steppe zone, with parts of the At wintering and migration stop-over sites 2006) and Uzbekistan (April-May 2007 marsh having some characteristics of the the species appears to be something of a and April-May 2008). taiga, such as the presence of conifers. It generalist, found in both inland and is possible that the main breeding habitat coastal saline, brackish and freshwater Where next? of Slender-billed Curlew was further habitats. Coastal wetland complexes with To maximise the conservation gains from north, in the taiga, or further south even seashore, estuary, lagoon, brackish any find, the first priority is to search in the true steppe (Gretton et al 2002). marshes, saltmarshes, beaches, mudflats, wintering areas or sites where birds are arable and grazing land seem favoured. likely to stay for more than a few days, for Moult strategy Inland, the species has used salt lakes and example if they are moulting.The The post-breeding moult of Slender-billed dried-up fish ponds in areas of steppe and following north African and Middle Curlew is complete, and includes flight freshwater lakes and marshes, even in Eastern countries merit searches during feathers, wing coverts, body and tail. It montane areas (Gretton 1991). the winter months: occurs early in the year, from June to In many parts of the species’ former ● Morocco: the well-documented August; this is in contrast to the post- migratory and wintering range, for sightings at Merja Zerga on the Atlantic breeding moult of nominate Eurasian example in Morocco,Tunisia and Italy, coast are the best known in the last 30 Curlew, which doesn’t start until early the available habitat and food supply has years, with 30 verified records since July and is completed by early October. diminished.This is often due to large- 1980 from September to February. The eastern orientalis form of Eurasian scale drainage, irrigation, water supply ● Tunisia: seven of the 10 sightings since Curlew starts its primary moult later still, and flood control schemes.Wars in Iraq 1980 were from Kairouan and Monastir mostly from mid-August to mid- and Iran have also impacted on large areas down to Sfax, from November to September, with completion by of marshland that are now rendered February and in September. December, though there is overlap with unsuitable as stop-over habitat, due to ● Algeria: the last two counts of more the nominate form. drainage and pollution. than 30 birds came from here in The timing of Slender-billed Curlew’s The only food items recorded for the January 1982. moult could indicate that birds start species have been insects and their larvae, ● Iran: there were 15 records in Iran shedding their feathers near their molluscs, crustaceans and annelid worms. during the 1990s; 12 in January, with breeding sites as, according to Ushakov, Feeding behaviour has been seen to all but one, in the Gulf of Oman, on the after fledging in early July the “birds stay involve pecking and probing, and in Persian Gulf, plus one in February, as around the nesting area for quite a long shallow water, the species has been noted well as in May and October on the time”. After breeding, he said that moving more quickly than Eurasian south-east coast of the Caspian Sea. migration probably starts “in the second Curlew, recalling Spotted Redshank ● Oman: two of the last verified records half of August”. However, this would be (Glutz von Blotzheim et al 1977). of Slender-billed Curlew were from unusual for a Numenius species, and is here in 1999. certainly untrue according to the new Searches so far ● Iraq: the last of five records, spanning isotope data that show a very clear In the past 19 years there have been at September to January, was in 1979. separation between adult and juvenile least 17 expeditions, all unsuccessful, to ● Egypt: the last of six records, between feathers, the latter having been grown on try to locate Slender-billed Curlew at September and February, was in 1980. the breeding grounds (Geoff Hilton, pers wintering, breeding and passage sites. So too would the following European comm). These expeditions have varied in time countries with winter records since 1980: Flight-feather moult is occasionally from two or three days to more than six ● Italy: the Gulf of Manfredonia had 19 suspended, and then completed in weeks.The most recent expeditions have verified sightings since 1980, from wintering areas before January-February. included Russia and Kazakhstan (1996- December to May and also in August. Juveniles undergo a partial moult, 97), Russia (Baraba and Karasuk steppe, ● Greece: the main site is the Evros Delta, ៑

WWW.BIRDWATCH.CO.UK JANUARY 2009 • BIRDWATCH 45 consider their clinal intergrading , or forms, breeding further east. These share more common features with Slender-billed Curlew than nominate Eurasian Curlew and Whimbrel.They are the eastern orientalis race of Eurasian Curlew, breeding east of the Urals, and suschkini Eurasian Curlew and alboaxillaris (‘Steppe’) Whimbrel, both rare and breeding in steppe regions of southern Russia and Kazakhstan. Therefore, searching for Slender-billed Curlew requires a broad knowledge of the two more common and widespread

RICHARD PORTER curlew species in the Western Palearctic, A Slender-billed Curlew (left) with a including their variability in plumages Eurasian Curlew and other waders in or Kazakhstan, with birds peeling off and size.Within the species, females north Yemen in January 1984. Could southwards down a succession of average larger and heavier, and have such under-explored countries still increasingly westerly routes. longer bills. Bills of juveniles are much provide refuge for this species in winter? Birds that used the more western paths shorter in summer and will attain final presumably went north of the Caspian Sea length only in their first autumn. Freshly with 28 verified records since 1980, to the Azov and Black Seas, stopping at the moulted feathers are darker and show mainly in spring, but also in August and Crimean wetlands and Danube Delta.They stronger contrasts than older faded ones. October, and from December to would head for the Pannonian Plain of The distinguishing characteristics of February. Sites without wintering Hungary and Serbia, and finally down the three species are compared and records include Porto Lagos, with eight through either France and Spain to summarised in detail in the ID ‘toolkit’ verified records since 1980, mainly Morocco, or via Italy and Malta to Algeria accompanying this issue – please refer to April-June, but also August and and Tunisia. the table on page 3 of the toolkit for September.The second last verified More central routes seem to exist, for detailed information. record of the species comes from the example down through Bulgaria into Evrotas Delta in April 1999. Greece or continuing down through Stable isotope research ● Hungary: five birds were reported from Turkey to Egypt and the Red Sea, and The RSPB is nearing completion of a the Hortobágy region in September perhaps onward to Yemen.A more easterly research project involving stable isotope 2002, and there have been seven route ran down along the Caspian Sea and analysis of carbon, nitrogen, hydrogen verified records since 1980, from eastern Black Sea to the Persian Gulf, and hopefully strontium.This entails September-December and in May. perhaps to Iran and Iraq, and the Arabian studying Slender-billed Curlew feathers ● Bulgaria: the Burgas region of the Black Sea, Oman. Migrant and wintering from a number of international museum Sea coast has produced most records, Slender-billed Curlew could still collections in order to examine their especially in autumn – 11 since 1980, potentially be found on suitable habitat geographical origins.This forms part of in September, November-January,April anywhere along these routes. the RSPB’s continuing commitment to the and May. Stable isotope work might help narrow work of the Slender-billed Curlew ● Ukraine: since 1980 there have been down some potential breeding areas in Working Group (SBCWG). nine records from the Danube Delta – Siberia, or perhaps in the steppes of The work offers the possibility of July to October and April – and eight Kazakhstan or on passage in Uzbekistan. delimiting Slender-billed Curlew breeding from the Lebyazhy Islands Reserve on In any case, for observers travelling to areas, and ruling in or out potential the Crimean Black Sea coast, August- potential locations to look for this species, moulting sites. It could thus help refine October and April-May, and a winter please report any places and dates searched the search for the world’s remaining record exists from the 1970s. without any Slender-billed Curlew records Slender-billed Curlews. It is strange that there are no verified including, if possible, any information on The analysis involves measuring the 20th-century records of Slender-billed habitats and threats, including habitat proportions of different stable isotopes of Curlew from Spain, considering that the changes and disturbance. a given element in a sample, such as a species used to regularly winter in feather. Isotope ratios in a sample vary Andalucia in the 19th century. Identification depending on where, geographically, that Relative to the other two European Successful conservation of Slender-billed tissue was grown (among other factors, Numenius species, but in common with Curlew depends on reliable data.These such as habitat and diet). For example, the Eskimo Curlew, Slender-billed Curlew can only be obtained if every record of a proportions of strontium stable isotopes appears to have a relatively inland possible Slender-billed Curlew is carefully in a feather will vary according to the migration route. Past records from before distinguished from Eurasian Curlew and origins of the rocks from which the metal the decline suggest that the species moved Whimbrel.This is by no means easy, originally came, before being ingested by west from its breeding grounds in Siberia especially as observers also need to the bird in its food.

46 BIRDWATCH • JANUARY 2009 WWW.BIRDWATCH.CO.UK Species spotlight

Once grown, feathers retain the since mid-2008 it has been chaired by have also outlined research, especially on isotopic ‘signature’ of the place where Nicola Crockford, with Tim Cleeves as the the use of stable isotope analysis, as a tool they were grown, regardless of where the database and fieldwork co-ordinator. to track down this most threatened bird subsequently moves. Furthermore, Its activity is guided by the species in the Western Palearctic. the isotope signature will remain international action plan for the species. All we need now is for you to find unchanged in the feather even after many This was published in 1996, and is now one, or make it possible for others to find decades in a museum. Birds in their first in the process of revision.The most recent one. So please do whatever you can to autumn/winter will have juvenile flight draft of the revision dates back to 2002, help, and check those curlews – the feathers that were grown on the breeding and it is intended to finalise it by 2010 Slender-billed Curlew challenge is on! ■ sites, while adult birds will have flight for approval by governments. feathers grown at the post-breeding One of the key roles of the SBCWG is Acknowledgements moult sites. By sampling a range of to maintain the database of records of For their help in various ways, we museum skins, we have the potential to Slender-billed Curlew and the would like to thank Loraiza Davies, Lucy obtain information about both areas. bibliography.Another is to catalyse Arnold, Paul Britten and Ian Fisher at the The second part of the project is to research, especially to help locate the RSPB, Adam Gretton, Sergey Dereliev, ‘ground-truth’ the Slender-billed Curlew bird. Historical data on habitat preference Geoff Hilton, Nicola Baccetti, ACBK, isotope signatures using feathers of and diet throughout the range needs RBCU, those European museums which similar species from across the potential to be compiled and an analysis of the allowed the sampling of feathers from range, to create an ‘isotopic map’. distribution of suitable habitat conducted. their Slender-billed Curlew collections, It might also be instructive to examine Heinz-Otto Rehage at the LWL-Museum Co-ordinated action the wet/dry cycle in relation to für Naturkunde Münster, Didier Slender-billed Curlew is subject to the reproduction and distribution by Vangeluwe at the Institut Royal des highest level of protection under the examining Russian meteorological data, Sciences Naturelles de Belgique and relevant international treaties. In 1994 and to undertake a comparative study of George Handrinos of the Greek Minstry the Convention of Migratory Species other declining waders of similar habitats, of Agriculture. (CMS) established a Memorandum of such as ‘Steppe’Whimbrel, Sociable Understanding (MoU) concerning Lapwing and Eskimo Curlew. REFERENCES conservation measures for the species At the moment the work operates • BirdLife International. 2008a. Species factsheet: Haematopus meadewaldoi. Downloaded from (see www.slenderbilledcurlew.net) which without a budget, although the RSPB is www.birdlife.org on 11/9/2008. has now been signed by 18 of the species’ undertaking the isotope work and • BirdLife International. 2008b. Species factsheet: 30 range states, as well as 13 potential underwrites the costs of the SBCWG, Numenius borealis. Downloaded from www.birdlife.org on 11/9/2008. range states, although unfortunately not including the roles of chairman and • Cramp, S, and Simmons, K E L (eds). 1983. The yet Russia. co-ordinator. Further funds are now Birds of the Western Palearctic. Vol III. Oxford In the framework of the MoU, to needed, especially for search expeditions. University Press, Oxford. • Danilenko, A K, Boere, G G, and Lebedeva, E A. co-ordinate concerted action for the 1996. Looking for the recent breeding grounds of species, the SBCWG was established in Conclusion Slender-billed Curlew: a habitat-based approach. 1997.After several years of dormancy, We trust that those who seek to follow the Study Group Bulletin 81: 71-78. • Ewins, P J. 1989. Slender-billed Curlews in quest to find Slender-billed Curlew now Morocco in February 1979. Dutch Birding 11: 119-120. Curlews in adult plumage (reproduced have all the basic information they will need.We have suggested where and when • Glutz von Blotzheim, U N, Bauer, K M, and Bezzel, from the toolkit enclosed with this E. 1977. Handbuch der Vögel Mitteleuropas. Bd 7. issue). From left: Eurasian Curlew (N a the birds are most likely to be found, Akademische Verlagsgesellschaft Wiesbaden. arquata and N a orientalis), Whimbrel including giving relevant clues (where • Gretton, A. 1991. The ecology and conservation of and Slender-billed Curlew. Compare known) regarding their ecology, and have the Slender-billed Curlew (Numenius tenuirostris). (Monograph 6). International Council for Bird size, bill shape and length, head provided detailed guidance to help markings, and the pattern of the Preservation, Cambridge. • Gretton, A. 1994. An estimate of the current upperwings, underwings and tail. identify the species in the field, report it and seek verification of any records.We population of the Slender-billed Curlew. In: Preparation d’un plan de sauvetage pour Numenius tenuirostris. Final Report to the European Commission. Annex 5. Vol. 2. • Gretton, A, Yurlov, A K, and Boere, G. 2002. Where does the Slender-billed Curlew nest? British Birds 95: 334-344. • van den Berg, A B. 1988. Identification of Slender- billed Curlew and its occurrence in Morocco in winter of 1987/88. Dutch Birding 10: 45-53. • Ushakov, V E. 1909. The Slender-billed Curlew Numenius tenuirostris. Nasha Okhoto 2: 92-95. • Ushakov, V E. 1912. More on the Slender-billed Curlew in Tara region. Nasha Okhoto 17: 27-32. • Ushakov, V E. 1916. Nest and eggs of Numenius tenuirostris. Orn Vestnik 3: 185-187. • Ushakov, V E. 1925. Colonial nesting of the Slender-billed Curlew in Tara district of Omsk province. Ural’skiy okhotnik 2: 32-35. CHRISTOPHER SCHMIDT

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